Antimicrobial potential and taxonomic investigation of piezotolerant Streptomyces sp. NIOT-Ch-40 isolated from deep-sea sediment

Abstract

Microbial-derived natural products from extreme niches such as deepsea are known to possess structural and functional novelty. With this background, the present study was designed to investigate the bioprospecting potential and systematics of a deep-sea derived piezotolerant bacterial strain NIOT-Ch-40, showing affiliation to the genus Streptomyces based on 16S RNA gene similarity. Preliminary screening for the presence of biosynthetic genes like polyketide synthase I, polyketide synthase II, non ribosomal peptide synthase, 3-amino-5-hydroxybenzoic acid synthase and spiroindimicin followed by antibacterial activity testing confirmed the presence of potent bioactivity. The secondary metabolites produced during fermentation in Streptomyces broth at 28 °C for 7 days were extracted with ethyl acetate. The extract exhibited a specific inhibitory activity against Gram-positive bacteria and was significantly effective (p < 0.0001) against methicillin-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentration and minimum bactericidal concentration against MRSA was 1.5 µg/mL, which was statistically significant in comparison with erythromycin. A multifaceted analysis of the Streptomyces spp. was carried out to delineate the strain NIOT-Ch-40 at a higher resolution which includes morphological, biochemical and molecular studies. Piezotolerance studies and comparison of fatty acid profiles at high pressures revealed that it could be considered as one of the taxonomic markers, especially for the strains isolated from the deep sea environments. In conclusion, the observation of comparative studies with reference strains indicated towards the strain NIOT-Ch-40 as an indigenous marine piezotolerant Streptomyces sp. with a higher probability of obtaining novel bioactive metabolites.

Exploring the hidden treasures: Deep-sea bacterial community structure in the Bay of Bengal and their metabolic profile

“…The prevalence of extremities in the deep-sea environment supports unique habitats and biota (Sogin et al, 2006;Ramirez-Llodra et al, 2010). The deep-sea microorganisms, in particular, exhibit remarkable metabolic adaptations that enable them to thrive in extreme and often harsh environments (Padmanaban et al, 2017;Garel et al, 2021). Due to the absence of sunlight in the deep ocean, these microbes rely on chemosynthesis rather than photosynthesis for energy production.…”

“…The Bay of Bengal (BOB) forming the northeastern part of the Indian Ocean is the largest triangular basin in the world, that is approximately 2090 kilometres long, 1600 kilometres wide and has an average depth of approximately 2600 metres (Jasna et al, 2020). Multiple riverine influxes (1.6 × 10 12 m 3 yr -1 ; UNESCO, 1979) from the Indian subcontinent and Himalayan range, such as the Ganges, Brahmaputra, Irrawaddy, and Salween on the north and Mahanadi, Godavari, Krishna, and Kaveri on the west, deposit sediments in BOB, supporting a complex marine microbiome (Varkey et al, 1996;Padmanaban et al, 2017;Angelova et al, 2019). Studies in the BOB focussing on benthic bacterial diversity remain underrepresented and have gained impetus only in recent years (Verma et al, 2017;Rajpathak et al, 2018;Angelova et al, 2019;Padmanaban et al, 2019;Lincy and Manohar, 2020;Parvathi et al, 2020;Gu et al, 2022;Guo et al, 2022;Marimuthu et al, 2022).…”

Complete genome of mangrove-derived anti-MRSA streptomycete, Streptomyces pluripotens MUSC 135T

“…Members of genus Streptomyces are known to produce various types of compounds with bioactivities includ-ing anticancer, antioxidant, antifungal and antibacterial properties [1][2][3][4][5][6][7] . The unique life cycle of streptomycetes have enhanced their ability to persist in nature and to survive in harsh environmental conditions [8][9][10][11][12][13] . Streptomyces pluripotens MUSC 135 T was firstly isolated as novel strain from mangrove forest in Peninsular Malaysia during a screening program for antibiotic producers [14,15] .…”